libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/deduction.cc

   1 // Copyright (C) 2017-2020 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++17" }
  19 // { dg-do compile { target c++17 } }
  20 // { dg-xfail-if "COW string missing deduction guides" { ! cxx11-abi } }
  21
  22 #include <string>
  23 #include <testsuite_iterators.h>
  24
  25 template<typename T, typename U> struct require_same;
  26 template<typename T> struct require_same<T, T> { using type = void; };
  27
  28 template<typename T, typename U>
  29   typename require_same<T, U>::type
  30   check_type(U&) { }
  31
  32 void
  33 test01()
  34 {
  35   std::wstring s0;
  36   std::allocator<wchar_t> a;
  37
  38   std::basic_string s1 = s0;
  39   check_type<std::wstring>(s1);
  40
  41   std::basic_string s2 = std::move(s0);
  42   check_type<std::wstring>(s2);
  43
  44   const std::basic_string s3 = s0;
  45   check_type<const std::wstring>(s3);
  46
  47   const std::basic_string s4 = s2;
  48   check_type<const std::wstring>(s4);
  49
  50 #if _GLIBCXX_USE_CXX11_ABI
  51   std::basic_string s5(s0, a);
  52   check_type<std::wstring>(s5);
  53
  54   std::basic_string s6(std::move(s0), a);
  55   check_type<std::wstring>(s6);
  56 #endif
  57
  58   std::basic_string s7(s0, 0, 0);
  59   check_type<std::wstring>(s7);
  60 }
  61
  62 void
  63 test02()
  64 {
  65   using namespace __gnu_test;
  66   wchar_t a[1] = {};
  67   test_container<wchar_t, input_iterator_wrapper> seq(a);
  68
  69   std::basic_string s1(seq.begin(), seq.end());
  70   check_type<std::wstring>(s1);
  71
  72   std::basic_string s2(seq.begin(), seq.end(), std::allocator<wchar_t>());
  73   check_type<std::wstring>(s2);
  74
  75   std::basic_string s3((wchar_t)1, L'a');
  76   check_type<std::wstring>(s3);
  77
  78   std::basic_string s4((wchar_t)1, L'a', std::allocator<wchar_t>());
  79   check_type<std::wstring>(s4);
  80 }
  81
  82 void
  83 test05()
  84 {
  85   // LWG 3075 basic_string needs deduction guides from basic_string_view
  86   std::wstring_view sv{L"A View to a Kill"};
  87   const std::allocator<wchar_t> a;
  88
  89   std::basic_string s1(sv);
  90   check_type<std::wstring>(s1);
  91
  92   std::basic_string s2(sv, a);
  93   check_type<std::wstring>(s2);
  94
  95   std::basic_string s3(sv, 2u, 6u);
  96   check_type<std::wstring>(s3);
  97
  98   std::basic_string s4(sv, 2u, 6u, a);
  99   check_type<std::wstring>(s4);
 100 }
 101
 102 void
 103 test06()
 104 {
 105   // LWG 3076 basic_string CTAD ambiguity
 106   using namespace std;
 107   wstring s0;
 108
 109   basic_string s1(s0, 1, 1);
 110   check_type<std::wstring>(s1);
 111
 112   basic_string s2(L"cat"sv, 1, 1);
 113   check_type<std::wstring>(s2);
 114
 115   basic_string s3(L"cat", 1);
 116   check_type<std::wstring>(s3);
 117 }